/Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Selection/MeshTopologySelectionMechanic.h
Selection API Intersect the ray with the mesh and update the selection based on the hit element, modifier states, etc
true if selection was modified
virtual bool UpdateSelection ( const FRay & WorldRay, FVector3d & LocalHitPositionOut, FVector3d & LocalHitNormalOut )